Heretofore, various electronic components, each of which requires a sealing structure, such as a piezoelectric vibration component including a piezoelectric vibration element, for example, have been used. In the electronic component having a sealing structure as described above, in general, a sealing member is adhered to an electronic component body with an adhesive.
The sealing member is generally formed of a material, such as a metal, having a low air permeability. However, the air permeability of the adhesive is relatively high. Accordingly, an internal gas may leak through an adhesive layer, or external air, moisture, and the like may flow into an airtight room through the adhesive layer. Hence, an adhesive having a low air permeability has been increasingly and strongly desired.
For example, the following Patent Literature 1 has disclosed as an adhesive composition used to seal an electronic component, an adhesive composition containing an epoxy resin, a curing agent, inorganic fillers, and a rubber component as essential components.    PTL 1: Japanese Unexamined Patent Application Publication No. 2003-277711